Communication devices often use clock signals to control synchronous circuits. The clock signals may be distributed throughout the communication device through dividers, buffers, repeaters, and/or other suitable circuits. For example, a communication device may include a clock synthesizer to generate a root clock signal. The root clock signal may be processed by a frequency divider to divide a frequency of the root clock signal by two and create a clock signal with a 50% duty cycle. The clock signal may then be distributed through clock buffers and/or clock repeaters to circuits within the communication device.
Some communication devices may include multiple wireless transmitters to transmit multiple data streams, and may include multiple wireless receivers to receive multiple data streams, for example, to increase communication bandwidth. These communication devices, which may operate in multiple-input multiple-output (MIMO) systems, typically offer increased peak data rates, increased spectral efficiency, and increased quality of service by communicating with each other using a plurality of parallel data streams (e.g., as compared with communication devices that transmit a single data stream).
Communication devices operating in MIMO systems may include a plurality of radio frequency (RF) transmit chains, each of which may transmit a corresponding one of a plurality of data streams. For multiple transmit chains to transmit multiple data streams at the same time, it is important that the clock signals provided to the multiple transmit chains are (and remain) synchronized with each other. Thus, there is a need to improve timing synchronization between clock signals provided to multiple transmit chains of a communication device that operates in a MIMO system.